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Plebejus glandon megalo Hübner, [1819]
Arctic Blue
Family: Lycaenidae (Gossamer Wings)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia.
Introduction to the Lepidoptera of BC
Introduction to the Butterflies of BC
The Families of Lepidoptera of BC

Photograph

© Ian Gardiner     (Photo ID #5804)

Map

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Distribution of Plebejus glandon megalo in British Columbia.
(Click on the map to view a larger version.)
Source: Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Species Information


Adult

The Arctic Blue is easily distinguished by the ventral hindwing, which has a postmedian area of almost fused white spots. Both sexes have this characteristic. The upperside of the male wings is steel blue. In northern populations, the blue is interrupted by areas of dark scales. Females in southern populations have a brown ground colour. On the upperside of the female forewings there is a median row of white spots with small black centres. Females of northern population have this same pattern overlaid by steel-blue scales.

Immature Stages

Hardy (1963) partially described the immature stages of a Vancouver Island population of the Arctic Blue. The egg is white, flattened, and turban-shaped. The second instar larva has a rich, vinaceous purple head. The body has a pair of faint subdorsal lines on a honey-coloured ground colour.

Subspecies

Populations in most of BC are the subspecies A.g. megalo (McDunnough, 1927) (TL: Mt. McLean, Lillooet, BC). In these populations, the upperside of the wings of females have obvious postmedian white spots on forewings and hindwings. Populations from the Peace come close in appearance to the Canadian Prairie subspecies, A.g. lacustris (T. Freeman, 1939) (TL: Norway House, MB). These populations have females with faint postmedian white spots on both upper wings. The ground colour is the same grey. Bird et al. (1995), Klassen et al. (1989), and Layberry et al. (1998) erred in applying the name A.g. rustica (W.H. Edwards, 1865) (TL: Empire, Clear Creek Co., CO) to the Canadian Prairie populations. Hooper (1986), correctly, did not use the taxon rustica for Saskatchewan. In the southern Rocky Mountains subspecies,A.g. rustica, the upper surface of the female wings is a uniform chocolate brown. The Prairie subspecies is grey with a visible pattern of spots, similar to megalo.

Genus Description


The name Agriades most likely means "like argus," another European blue. The original Argus, from the myth of Zeus and Io, had 100 eyes, a reference to the many spots on the underside of the wings (Emmet 1991).

The major structural differences that have defined this genus are the falces and labides of the male genitalia. The falces is elongate and extends to just beyond the labides. In this characteristic, the genus is closest to Lycaeides and Vacciniina, and all three are far removed from lcaricia and Plebejus.

The genus Agriades has four species: one Palearctic, one Holarctic, and two Nearctic species restricted to California and southwestern Oregon. Emmel and Emmel (1998) clearly define two Californian species, but they do not clearly show that other taxa are not all A. glandon. Both European and North American authorities have tried to recognize more than one species within the species A. glandon, but so far no conclusive evidence has been published.

Biology


Peace River populations of the Arctic Blue fly from late May to late June. Other northern BC populations fly from early June to early August, depending on the timing of the spring snow melt. Southern alpine populations fly from late June to late August, again depending on the timing of the snow melt. All populations are univoltine. Hardy (1963) documented oviposition and larval feeding on Saxifraga bronchialis at Mt. Becher, Vancouver Island. Eggs were laid on 1 August and hatched on 13 August. Second instar larvae entered hibernation on 11 September. J. Pelham (pers. comm.) has observed oviposition on Saxifraga tricuspidata in the Yukon. Adults of the Arctic Blue have been associated with Saxifraga throughout most of BC. It is not clear whether this affiliation is related to oviposition or only to nectaring. In the Peace River area, J. Pelham (pers. comm.) has observed the Arctic Blue ovipositing on Oxytropis sp., but Shepard has seen it always in association with Saxifraga sp. in the same area. Scott (1992) has observed Colorado Arctic Blues ovipositing on species of Androsace that also occur in BC alpine habitat. Thus Saxifraga may be only a nectar source in parts of BC.

Habitat


The Arctic Blue is found throughout BC except for the Northern Mainland Coast and the Queen Charlotte Islands. In southern BC, the Arctic Blue is found above timberline. In northern BC, it is found at elevations from 500 to 2,000 m.

Distribution

Distribution

The Arctic Blue is found in central and northern AK and east across most of the Canadian Arctic to NF. In the west it ranges south to northern WA and southeastern MB, and south in the Rockies to NM.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
NativeS5YellowNot Listed



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